Synchronizing clock



June 14, 1938. E. A. FALLER 2,120,353

SYNCHRONIZING CLOCK Filed Dec. 18, 1935 2 Sheets-Sheet 1 '48 43 61 INVENTOR a2 45 7 5 ATTORNEY Patented June 14, 1938 UNITED STATES PATENT OFFICE SYNCHRONIZING CLOCK Application December 1a, 1935, Serial No. 54,995

7 Claims.

This invention relates to clocks and more particularly to clocks which may be corrected hourly by electric current impulses from a remote source.

In the use of time systems and particularly in the use of systems in which the clocks are operated from an electric power network of wellregulated frequency, the occasional interruptions of the supply from uncontrolled and unsuperyised sources cannot be prevented. Different l0 characteristics and conditions under which clocks operate also effect their time keeping qualities; so that synchronous motor drive clocks operating on the same circuit may differ from each other. Dirt or foreign matter temporarily lodged in the gear train may cause a load sumcient to cause a slippage of the armature in the rotating field of the motor to cause the clock to run slow. Unauthorized setting of the hands of a clock is sometimes resorted to where a deliberate attempt to mislead as to the time is desired by the one making such a setting. To compensate for such instances it is necessary to provide means for individually and automatically correcting each clock periodically and for providing means whereby an unauthorized setting of a clock cannot be made to exceed the correcting range of the clock.

All object of the invention is to provide means for hourly correcting a clock by means of electric current impulses.

Another object is to provide blocking means for preventing unauthorized setting of a clock by an amount exceeding the corrective range of said clock.

A still further object is to provide means for continued operation of the clock upon failure of the corrective mechanism to function on account of current failure or other reasons.

Other objects and advantages of this invention will be apparent from the specifications and the accompanying drawings which show one embodiment of-this invention and wherein similar reference numerals indicate similar parts and wherein in the drawings:

Fig. 1 shows a front elevation of the clock mechanism.

Fig. 2 shows a. side elevation looking towards the right side of Fig. 1.

Fig. 3 shows a side elevation looking towards the left side of Fig. 1.

Fig. 4 shows a plan view of the clock movement.

Fig. 5 shows an enlarged view of a detailed part u of the mechanism.

Fig. 6 shows a detail of parts of Fig. 1 in a different position.

There are various and numerous methods of synchronizing a. network of clocks. The present device could readily be applied to most of the systems. In the present instance it may be contemplated that this device may be driven by a well known type of synchronous motor operating from a light and power network and directly connected to the main shaft l0 and that the magnet 39 may be in a timed circuit and responsive only to a current of a frequency substantially higher than the commercial current frequency. Such a method would require time controlled equipment for effecting impulses of such high frequencies over the light and power network. A complete and detailed description of such a control equipment may be found in the copending application of L. S. Harrison, Serial No. 17,245,

filed April 19, 1935.

Instead of the above method of synchronization the magnet 39 may be controlled by a third wire or additional circuit carrying impulses of the same commercial current as carried in the network.

The present mechanism might also have its shaft l0 connected with a spring drive clock mechanism either hand wound or motor wound,

and periodically corrected by means of current impulses under control of a suitable time controlled mechanism.

Inasmuch as the method and means of controlling synchronization externally of the present device plays no part in the present invention it is deemed unnecessary to complex the description of the device with additional unnecessary description of existing art, as it will be accordingly assumed that the shaft I0 is directly connected to an alternating current synchronous motor or any other suitable device which normally turns shaft ill at a continuous and constant speed of substantially one-revolution per minute in a clockwise direction.

The shaft III is journaled in plates and I2 which are spaced apart and held in rigid alinement by pillars I3 all of which constitute the supporting framework of the mechanism. A gear I is fixed to the shaft l0 and a pinion I5 is rotatably mounted on said shaft and is connected to the gear I by means of the gears l6 and I1. The gears l6 and I! are fixed to a. shaft 22 which is journaled at one end in a bridge I! mounted on a spider iii. The bridge and spider are mounted on a ratchet wheel 20 by means of pillars 2i and the ratchet wheel 20 is rotatably mounted on the shaft i8 as also is the spider II. The opposite end of the shaft 22 is iournaled in the ratchet wheel 28 and said shaft has fixed thereto a leaf spring 23 which bears against the side of the ratchet wheel. As the shaft I8 rotates, the gear M will tend to rotate the gear l1 but due to the slight friction of the spring 23 the gear l4 does not rotate relative to the spider but the'whole spider assembly will rotate so that the gears i4, i1, i8, and I5 remain motionless relative to each other with the result that the pinion i5 is rotated at the same speed as the shaft i8, namely, 1 R. P. M.

Minute hand 18 and the hour hand 14 are mounted on arbors 38 and 34 respectively and cooperate with a suitable clock dial 15 which may be suitably mounted adjacent said hands, to indicate the time.

The clock hands are driven from the pinion l5 through the following gear train: Gear 24 engaged with pinion l5 and fixed to a shaft journaled in the frame plates II and I2, pinion 25 fixed to the same shaft to rotate with gear 24, idler gear 28 pivotally mounted on a stud in plate II and engaging pinion 25 and gear 21, gear 21 fixed to a shaft 28 which is journaled in the plate l2 and a struck-out portion 28. Fixed, by means of a bushing to the shaft 28 is a. spring 38 (Fig. 3) which frictlonally bears against the face of a gear 3| rotatably mounted on the shaft 28 and having integral with it a pinion 32. The pinion 32 engages a gear 33 on which is mounted the hour hand arbor 34 and the gear 3| engages a gear 35 on which is mounted the minute hand arbor 38. The gear 3| is rotated with the shaft 28 by virtue of the friction spring 38. A cam disc 31 is mounted on the minute hand arbor and rotates 1 revolution per hour with the gear 35, the purpose of which will be described later.

A magnet yoke 38 is mounted between the plates II and i2 and supports thereon a magnet 38 which cooperates with an armature 48 fixed to a lever 4| pivoted at 42. The lever 4| is provided with a semi-cylindrical pin 43 located between its pivot and the armature and has an offset 44. The lever 4| is biased in a counterclockwise direction by means of a spring 45 anchored between studs mounted on the front side of the lever and the back side of plate Fixed at the top of the lever 4| is a cam 48 which extends across the top of plate II and a ratchet wheel 41 and is formed downwardly to extend into the orbit of a pin 48 mounted on said ratchet wheel.

The ratchet wheel is pivotally mounted on a stud 48 and is normally biased in a clockwise direction by a coil spring 58 anchored to the ratchet wheel at one end by pin 5| and fixed at the other end to the clutch 48. The teeth in this ratchet wheel are adapted to be engaged by a pin 52 eccentrically mounted in the shaft 8 (Fig. 5) so that upon each revolution of the shaft the pin will rotate the ratchet wheel 41 an angular distance equivalent to one tooth. The

shaft l8 terminates at its forward end flush with the plate The extent of rotation-of the ratchet wheel 41 is limited in both directions by the cam plate 48.

The oflset end 44 of lever 4| is adapted to be engaged by one end 53 of a lever 54 lying in the plane of lever 4| and fixed to a shaft 55 Journaled in the plates H and I2. Fixed to said shaft 55 is a pawl 58 lying in the plane of the ratchet wheel 28 and adapted to engage the teeth thereon. A spring 51 attached between said pawl and a stud in plate I 2 normally biases the pawl 58 and shaft 55 in a clockwise directlon. The pawl 58 may be prevented from engaging the teeth of ratchet wheel 28 by the engagement of the lever 54 by the offset 44 or by the engagement of a pin 88 mounted on an arm of lever 54, with a projection 58 of a cam plate 31, as shown in Fig. 1. The pin 58 extends through an aperture in the plate II to the cam 31.

A lever 88 is pivotally mounted on a stud 8| mounted on plate II and is biased in a clockwise direction against a stop 18 by a spring 82. A projection 83 integral .with said lever extends into the orbit of a pin 84 mounted on the cam plate 31. At its upper end the lever is provided with a hook 85 and a projection 88. Normally the lever 88 takes the position shown in Fig. 6. A leaf spring 81 is mounted on the lever 88 and is provided with a pawl 88 which engages the teeth of the ratchet wheel 41 when the lever is in its normal position as shown in Fig. 6. When said lever is rocked to the left the pawl 88 becomes disengaged from the ratchet wheel as shown in Fig. 1.

A counterbalance 88 is provided at the bottom of the spider l8 to balance the weight of the bridge l8 and the gear wheel mounted thereon.

Operation Normally the magnet 38 is deenergized so that the armature is in the position shown in Fig. 8. Any suitable master clock such as for example is shown.in patent to J. W. Bryce, No. 1,380,818, dated September 6, 1921, may be used which will close a contact for one-minute duration over a circuit running to the magnet 38 to initiate a flow of current from a suitable source for that duration. Such provisions are old and wellknown in the art and further description of the same is deemed unnecessary for a clear understanding of the present invention. In the present invention the master clock will close such a circuit when the chronological position of the master clock is at the'59th minute and open at the even hour. Thus, the operation of the magnet 38 is limited to energization for a oneminute period each hour.

In the patent above cited a cam on the minute hand shaft cooperating with a single contact will suffice.

The projection 58 on the cam 31 will arrive under the pin 58 on lever 54 at the chronological position of the motor drive clock of 38 seconds after the 59th minute. The secondary clock normally running rotates the pinion I5 at the same rate the main shaft l8 rotates with the spider I8 rotating about its axis.

The cam 31 is movable with the hands or time indicating mechanism of the clock and is operable independently of the ratchet wheel 41 by means of the friction drive spring 38, that is so that the cam 31 may be blocked and so block the advance of the time indicating mechanism, whereas the main shaft M will keep turning and consequently advance the ratchet wheel 41. The pin 84 on cam 31 will reach'and impinge on the projection 83 when the chronological position of the time indicating members, or the minute hand of the motor drive clock reaches approximately its 59th minute position. The lever 88 will be urged in a counterclockwise direction but the hook 85 will engage the pin 43 (Fig. 6) and prevent this. Thus, if the clock has been set ahead by some unauthori. 6. person, it can move no further than this position and it will be halted'there until the master clock reaches its 59th minute position, whereupon the magnet 39 becomes energized and the pin 43 on lever 4| will be moved downwardly intothe path of the projection 66. At this time the lever 63 still urged by the motor driving the friction spring 36 will move to the left, permitting the cam 31, and thus the hands of the clock, to move forward one minute halting the clock at its even hour position by virtue of the pin 43 impinging against the projection 65, as shown in Fig. 1. When the master clock reaches its even hour position the circuit to magnet 39 is opened, and said magnet deenergized, permitting the pin 43 to rise and become disengaged with the projection 66.

The lever 63 being new unrestrained, permits the cam 31 to resume its rotation and the pin 64 will continue to move the lever 60 to the left until the pin is disengaged from the projection 63 after which the lever 60 will be swung to the right by spring 62 against the stop pin Ill and will take the position shown in Fig. 6. When the lever 60 rocks clockwise the cam shaped end 65 strikes the circular side of pin 43 camming it downward slightly so that it passes under the nose of the hook. The movement of the lever 4| about its pivot is not suiilcient however to disengage the oii'set 44 from the end 53 of lever 54. When the motor drive clock will be arrested by the pin 64 against projection 63 of lever 60, the chronological position of the clock will be at the 59th minute and therefore the projection 59 on cam 51 will not yet have arrived under pin 56. If the clock is ahead of the master clock the 59th minute impulse will not as yet have been initiated so that magnet 39 will not be energized and the end 53 of lever 54 will be engaged by the offset 44. When the 59th minute impulse energizes the magnet 39, the lever 54 will be released and move clockwise to cause pawl 56 to engage ratchet wheel 20 causing the hands to move ahead rapidly the equivalent of 30 seconds, in a manner to be explained later, until the projection 59 lifts the pin 58 to rotate lever 54 counterclockwise and disengage the pawl 56 after which the clock resumes advance at normal speed while the pin 64 bears against the projection 63 moving the lever 60 counterclockwise until the projection 66 strikes the pin 43 halting the progress of the time indicating mechanism of the clock at its 60 minute chronological position. Upon the deenerglzation of the magnet 39 the offset 44 again engages the lever end 53 and the clock resumes its normal advance as previously explained.

If the motor drive clock is slow at the time magnet 39 is energized the projection 59 will not have reached the pin 56, consequently, when the lever 4| is rocked clockwise the offset 44 disengages the end 53 of lever 54 and said lever is rocked clockwise by spring 51 causing the pawl 56 to engage the ratchet wheel 23 and arrest its rotation. The stopping of this ratchet wheel arrests the rotation of the spider and causes the pinion i to be rotated at such a speed that the minute hand arbor and therefore cam 31 now rotates at the rate of one-revolution per minute instead of one-revolution per hour.

The drive of the pinion I5 is now effected through the gear train in which gear wheel l4 fixed to drive shaft l6, still turning at l R. P. M., drives pinion I! fixed to gear l6 which in turn drives pinion l5. The motor drive clock thus rapidly advances until the projection 59 strikes the pin 58 thus rocking lever 54 counterclockwise and withdrawing the pawl 56 from the ratchet wheel 23 and permitting the clock to resume its normal speed. As previously stated. when the projection 56 reaches the pin 53 the chronological position of the clock will be about 30 seconds after the 59th minute so that in speeding ahead the clock may reach this Point a few seconds ahead of time to resume its normal speed thus being slightly ahead of the master clock. This will be compensated for, however, in the same manner as if the clock were fast and will be arrested at the hour position for the few seconds diflerence in time and will resume operation of the exact hour as previously explained.

If the clock is on time, when the magnet 35 is energized at the 59th minute as indicated by the master clock, the motor drive clock will also be at the 59th minute and the motor drive clock will speed up stepping ahead about 30 seconds until the projection 59 lifts the pin 53 as previously explained. The clock will then resume its normal speed for 30 seconds being arrested at the hour position until the master clock arrives at the hour position and then releases it.

It will be seen that if any unauthorized attempt was made to set the clock by turning the hand it could not be set forward or back in excess of an hour because the pin 64 would strike either the upper or the lower side of the projection 63 and in the following hour synchronization would be eii'ected. For authorized setting of clocks ahead an hour for daylight saving time, a manual switch could be provided in multiple with the master clock operated contact so that the circuit to magnet 39 could be closed manually right after a synchronizing period to allow the clock to run ahead under speed until the pin 64 again struck the projection 63 at which time the magnet would be deenergized and the clock allowed to resume its normal speed. Though the clock may be out of synchronism with the master clock during the next following hour, by an amount equal to the short time in which it took the minute hands to speed ahead one hour, it will be automatically connected at the next synchronizing period. When clocks have to be set back an hour due to the same reason, a manual switch may be provided for opening the circuit to all the driving motors for an hour, thus stopping all of the clocks for that period. Such a setting of clocks is done as a group as it affects all clocks in the same manner.

In event an interruption of the current supply to the motor driving the clock through shaft ill happens during a synchronizing period, provisions are made whereby the clocks will not be indefinitely held up due to failure of the.magnets to be energized and release the blocking means. As previously stated, the pin 52 eccentrically mounted in the shaft i0 engages the teeth of the ratchet wheel 41 advancing said ratchet one tooth per revolution of shaft III or one tooth per minute (Fig. 6). As the ratchet wheel is advanced each time, its advance is retained by the retaining pawl 68 and as this ratchet rotates it stores power in the spring 50. From its normal starting position to the point where the pin 46 impinges against the cam 46 there are 59 teeth on the ratchet 41 which may be engaged by the pin 52 so that it requires 59 revolutions of the shaft Ill, or 59 minutes for the pin 46 to travel from its position of rest to reach the cam 46. If synchronization occurs the cam is immediately released by the withdrawal of pawl 63 from the ratchet wheel when the lever 66 moves its first step to the left and said ratchet wheel is restored by the spring Ill. If, however, there has been an interruption in the current supply to the clock driving motor during the synchronizing period so that the ratchet wheel 41 was stopped prior to reaching that position and resumes operation when the current is restored after the synchronizing period has passed, there would be no operation of the magnet to release the hourly lock-up position of the movement. This condition is eliminated by the pin 48 which upon the picking up of the 60th tooth of the ratchet wheel by the pin 52 causes pin 48 to press against the cam 46 and so tilts lever 4| in the same manner as if the magnet 38 had been energized. This permits lever to move to the left, as previously described, removing the pawl 88 from ratchet wheel 41 so that said ratchet wheel is restored as before.

The clock will continue operation, although slow due to the current interruption, and will be corrected at the next synchronizing period. The 61st tooth in ratchet wheel 41 is omitted as shown at H (Fig. 5). This is in event that if anything should break or stick the high gear ratio between the motor and shaft Ill would not cause anything to be damaged as the pin 52 could continue to rotate harmlessly and could not attemptto force the ratchet beyond the 60th tooth.

While the fundamental and novel features of the invention have been shown and described and pointed out as applied to a single modification, it will be understood that various omissions and substitute changes in form and details of the device illustrated-and in its operation may be made by those skilled in the art without departure from the spirit of the invention. I intend to be limited therefor only as indicated by the scope of the following claims.

What is claimed is as follows:

1. In a clock mechanism having a continuously rotating shaft, 9. time indicating device driven by said shaft whereby the time indicating device is normally advanced at a time keeping rate, the combination of an electromagnetic device controlled by a master clock, speed accelerating means controlled by the operation of said electromagnetic device in accordance with certain chronological positions of said time indicating device for advancing said time indicating device at a more rapid rate than said normal time keeping rate, means normally in blocking position for blocking advance of the time indicating device beyond a certain chronological position, and means controlled by said electromagnetic device for rendering the blocking means ineffective to permit resumption of advance of the time indicating device.

2. In a, clock mechanism having a continuously rotating shaft, a time indicating device, and a gear train connecting said time indicating device with the shaft, whereby said time indicating device is normally advanced at a time keeping rate, the combination of a rotating member connected to said gear train and constantly driven at a uniform speed, a counting device operated by said rotatable member, blocking means for normally blocking advance of said time indicating device upon reaching a certain chronological position, means controlled by the counting device when it reaches a certain position of count for operating the blocking means to effect an unblocklng operation of said vreaches another chronological position,

device operated by said rotatable member, blocking means for normally blocking advance of said time indicating device upon reaching a certain chronological position, means controlled by the counting device when it reaches a certain position of count for operating the blocking means to effect an unblocking operation of said time' indicating device whereby said device may resume its normal advance, and means controlled by the blocking means for resetting the counting device upon said unblocklng operation.

4. In a clock mechanism having a continu-- ously rotating shaft, a time indicating device, and a differential gear train connecting said shaft with said time indicating device whereby said time indicating device is normally advanced at a time keeping rate, the combination of an electromagnetic device controlled by a master clock, locking means operated by the energization of said electromagnetic device at a certain chronological position of said time indicating device for looking a part of the differential train whereby the time indicating means is advanced at a rate more rapid than said time keeping rate, means advanced concurrently and in synchronism with the advance of said time indicating means for operating said locking means to unlock the differential train when said time indicating means and means for blocking further advance of said time indicating device upon reaching said last named chronological position, said last named means being operable upon deenergization of said electromagnet for unblocklng the advance of said time indicating device to permit the resumption of the advance of said time indicating device at the normal time keeping rate.

5. In a clock mechanism having a continuously rotating shaft, a time indicating device, and a differential gear train connecting said shaft and said time indicating device whereby said time indicating device is normally advanced at a time keeping rate, the combination of an electromagnetic device controlled by a master clock, locking means controlled by said electromagnetic device and said time indicating device and operable only in accordance with the chronological position of said time indicating device for looking a part of the differential gear train whereby the time indicating device is advanced at a rate more rapid than said time keeping rate, said locking means being operable by another chronological position of the time indicating device for unlocking the locking means from the differential gear train to terminate the more rapid advance of said time indicating device.

6. A clock mechanism including a constantly driven shaft, a time indicating device normally advanced thereby at a certain speed, meansfor periodically advancing said time indicating device at a speed greater than said certain speed when the time indicating device is behind standard time to advance it toa certain chronological position of said time indicating device, means controlled by said constantly driven shaft upon the time indicating device reaching said certain chronological position for rendering said speed advancing means ineflective, mechanism normally in blocking position for blocking advance of said time indicating device beyond said certain chronological position in advance of standard time, means for unblocking advance of said time indicating device when correct standard time agrees with said time indicating device, and an electromagnet controlled by a master clock for controlling the operation of said speed advancing means and said unblocking means.

7. A clock mechanism including a time indicating device normally advanced at a certain 15 speed, a standard time controlled element for periodically controlling the advance of the time indicating device at a speed greater than said certain speed when the time indicating device is behind standard time to cause the advance of said device at said greater speed to a certain chronological position of said time indicating device, mechanism normally in blocking position for blocking the advance ofv said time indicating mechanism beyond said certain chronological position in advance 01' standard time, and means controlled by said same element for unblocking the advance of said time indicating device whereby said device may resume advance at its normal speed.

ERNEST A. FAILER. 

